Whole house surge suppressor?

[bud--]

WOW!

You guys (gals if any) really have me thinking. I have wanted to update my ground rods to current standards (2 rods instead of 1) but haven't gotten to it in 10 years of owning the house. The " list " is ever changing if you follow me....

My "list" seems to only get longer.

Is it worth while to have say, 3 ground rods newly installed to help with the direction of transients when they occur? What do you think.

I know that ground rod resistance testing, they say, takes 3 rods to measure the resistance so that's where my ground rod guess comes from.

Two additional rods to measure the resistance of a rod does not suggest 3 rods should be used to earth a system. (There is now a clamp-on meter that can measure resistance to earth.)

Code only requires 2 as of right now. Any reason why 3 would not help or hurt performance?

If using ground rods as an earthing electrode the current NEC actually only requires 1, but the resistance to earth has to be 25 ohms or less. If you use 2 rods you don't have to measure the resistance, which is what most people do. If you have a code compliant single rod with 20 ohms to earth resistance, and connect 120V to it, the current will only be 6 amps. Ground rods are among the worst earthing electrodes. As I wrote earlier, for most new construction the NEC requires a "concrete encased electrode" (commonly called a Ufer ground). It is a good electrode. The lowest resistance to earth is likely a municipal metal water distribution system. (I just have a water service pipe as an earthing electrode. It was code compliant when installed and not a code violation now.)

I believe the NEC stops at 2 rods because there is a strong law of diminishing returns - the effect of more rods decreases. Adding a 3rd rod lowers the resistance, but not as much as the 2nd rod. A 4th rod will lower the resistance, but not as much as the 3rd rod.

Martzloff, the author of the NIST surge guide, has written "the impedance of the grounding system to `true earth' is far less important than the integrity of the bonding of the various parts of the grounding system." Check that there is a short ground wire from the phone, cable, dish entry protectors to a common connection point on the earthing system. The distance from the power service N-G bond also needs to be short. Long ground wires (as in the IEEE surge guide example starting page 30) can result in damaging voltages between power and signal wires. Short wires mean that during an 'event' that raises the ground potential at the house all wires will rise together.

Best protection is a "layered approach" as in Teken's post.

 

[gatchel]

Bud--,

I got ya. I have used Ditek products for years with success in the field and I have them in the home too. I installed new ground rod's at the house and added the second one at the garage as I planned originally but never got to do. Now the ground wire comes out of the bottom of the panel in the house and goes straight down about 4 feet, diagonally though the block wall and out to the ground ron another 8 inches. Then I have 2 more ground rods separated by 8 feet from each other.

The garage sub panel now has 2 ground rods, the first is about 5 feet of ground cable straight down to the rod located outside. The next rod is 8' away.

All of the other wiring from the dish and the wiring between the garage and house have surge devices at the entry points to each building and are properly bonded. This should be good enough now. My main concern was the old single ground rod that has been there since the house was built. Thanks for you suggestions. The links were good reading material, a good bit of which I knew from prior training.

 

[NJ Diver]

Re: Whol house surge suppressor?

Yes, and no.


Oh, and although it is counter-intuitive, they work best at the BOTTOM of the bus (assuming your main lugs are at the top).
This is due to the impedance issue above, and the high frequency wave nature of a surge. Installed at the top, more of the transient will continue down the bus to the end, and be reflected back. Installed at the bottom, the surge will travel down the bus (and not much will actually travel down each branch circuit because of their relatively high impedance compared to the rest of the bus in the panel), and instead of reflecting off the bottom, it will be absorbed by the TVSS.

So you are saying to have these as far away from the main lugs as possible? I don't think I have seen this on any of the other "how to" info I have been looking at. Even some of the install instruction PDFs I've read don't seem to identify this. They always seem to show them connected to the top left (with logs on top) Is that just their standard type of diagram? Just trying to confirm.

Also, how does one upgrade their grounding? Is that as simple as installing a second earth rod and connecting a cable between the two?

 

[westom]

Re: Whol house surge suppressor?

Is that as simple as installing a second earth rod and connecting a cable between the two?

Some basic electrical concepts apply. For example, a voltage is suddenly applied to one end of the wire. On what part of that wire is the voltage first seen? On its fartherest end. Voltage is last seen at the near end where voltage was first applied.

So is a best place to make a connection where a surge enters the bus? Or at the farthest end of that bus bar? Well, other factors (numbers) apply to make that discussion mostly irrelevant.

However, the point. Electricity does not work as so many only assume. Therefore rules for earthing start by asking what type of electricity is being addressed.

For simple 60 Hz power, earthing is only for human safety. Code defines what is is relevant - ie resistance. But earthing to also do surge protection is this topic. Earthing per code is insufficient. Other significant factors apply. Not resistance. Impedance is critical.

To layman, low impedance means a connection from the breaker box to earth that is less than 10 feet. Wire length (not wire thickness) is more important. Some reasons how and why were discussed in this post above in April 2012.

That wire from breaker box to earth must be as short as possible (ie 'less than 10 feet'). Must be separated from other non-grounding wires. Must have no sharp bends or splices. Must not be inside metallic conduit. And must connect to the same earthing electrode also used by telephone, satellite dish, and TV cable (the single point earth ground). Those other utility wires must also make the same 'low impedance' connection to the building's only and best earth ground. Any violation compromises surge protection. Because surge proetction is always about the only item that does protection - earthing.

Some will find their breaker box earthed by a solid quarter inch copper wire routed up over the foundation and down to earth ground. That means earthing is compromised. It violates most of the above guidelines. Same reasons often define a cold water pipe as an inferior earth ground.

Superior earthing means a ground wire goes through a foundation to connect to earthing electrodes. To eliminate sharp bends over the foundation. To separate it from other wires that connect to interior receptacles. And to make that connection feet shorter.

If using two earth ground rods, a connection is best one solid wire through a clamp on the first electrode and terminates at the second electrode. One uncut wire means lower impedance.

Those who did not do this stuff will argue resistance. When discussing surges, well, the same wire that can be 0.1 ohm resistance can also be 120 ohms impedance. 120 ohms is almost no connection. Impedance is why safety code rules are insufficient. Surge protection means earthing that also exceeds code requirements - for low impedance.

What defines surge protection? An item that absorbs hundreds of thousands of joules. Earth ground. The 'art' of protection is always about earthing.

Why does a power strip protector not claim to protect from destructive surges? Ground wire is more than 10 feet. Numerous splices. Too many sharp bends. May be inside metallic conduit. A power strip has no earthing. Near zero protection. One 'whole house' protector is massive protection when connected low impedance to single point earth ground. Above guidelines define a low impedance connection.

 

[wyliesdiesels]

Re: Whol house surge suppressor?

Wow, interesting read and a lot of conflicting statements! Does anyone get the feeling like I do that westom is copying and pasting from somewhere?

Some basic electrical concepts apply. For example, a voltage is suddenly applied to one end of the wire. On what part of that wire is the voltage first seen? On its fartherest end. Voltage is last seen at the near end where voltage was first applied.

So is a best place to make a connection where a surge enters the bus? Or at the farthest end of that bus bar? Well, other factors (numbers) apply to make that discussion mostly irrelevant.

However, the point. Electricity does not work as so many only assume. Therefore rules for earthing start by asking what type of electricity is being addressed.

For simple 60 Hz power, earthing is only for human safety. Code defines what is is relevant - ie resistance. But earthing to also do surge protection is this topic. Earthing per code is insufficient. Other significant factors apply. Not resistance. Impedance is critical.

To layman, low impedance means a connection from the breaker box to earth that is less than 10 feet. Wire length (not wire thickness) is more important. Some reasons how and why were discussed in this post above in April 2012.

That wire from breaker box to earth must be as short as possible (ie 'less than 10 feet'). Must be separated from other non-grounding wires. Must have no sharp bends or splices. Must not be inside metallic conduit. And must connect to the same earthing electrode also used by telephone, satellite dish, and TV cable (the single point earth ground). Those other utility wires must also make the same 'low impedance' connection to the building's only and best earth ground. Any violation compromises surge protection. Because surge proetction is always about the only item that does protection - earthing.

Some will find their breaker box earthed by a solid quarter inch copper wire routed up over the foundation and down to earth ground. That means earthing is compromised. It violates most of the above guidelines. Same reasons often define a cold water pipe as an inferior earth ground.

Superior earthing means a ground wire goes through a foundation to connect to earthing electrodes. To eliminate sharp bends over the foundation. To separate it from other wires that connect to interior receptacles. And to make that connection feet shorter.

If using two earth ground rods, a connection is best one solid wire through a clamp on the first electrode and terminates at the second electrode. One uncut wire means lower impedance.

Those who did not do this stuff will argue resistance. When discussing surges, well, the same wire that can be 0.1 ohm resistance can also be 120 ohms impedance. 120 ohms is almost no connection. Impedance is why safety code rules are insufficient. Surge protection means earthing that also exceeds code requirements - for low impedance.

What defines surge protection? An item that absorbs hundreds of thousands of joules. Earth ground. The 'art' of protection is always about earthing.

Why does a power strip protector not claim to protect from destructive surges? Ground wire is more than 10 feet. Numerous splices. Too many sharp bends. May be inside metallic conduit. A power strip has no earthing. Near zero protection. One 'whole house' protector is massive protection when connected low impedance to single point earth ground. Above guidelines define a low impedance connection.

Ummm....I think he was asking how to physically install a second rod NOT your version of the science behind earthing.

So you are saying to have these as far away from the main lugs as possible? I don't think I have seen this on any of the other "how to" info I have been looking at. Even some of the install instruction PDFs I've read don't seem to identify this. They always seem to show them connected to the top left (with logs on top) Is that just their standard type of diagram? Just trying to confirm.

Also, how does one upgrade their grounding? Is that as simple as installing a second earth rod and connecting a cable between the two?

The best way is to pound in a second 8' ground rod that must be 6' from the first. Connect the 2 with a #6 solid cu wire that continues on to the service panel neutral/grnd bar.

 

[Thruxton]

Re: Whol house surge suppressor?

Deleted

 

[wyliesdiesels]

Re: Whol house surge suppressor?

Deleted

What was deleted?

 

[NJ Diver]

I'm still curious if anyone else has heard of setting these up at the farthest slot from the lugs.

 

[wyliesdiesels]

FWIW- When I watch episodes of Mike Holmes where they install these, I do notice that it's always installed @ the bottom of the panel!

 

[ezzzzzzz]

I'm not going to read through this whole diatribe. I work in a network environment worth millions of dollars. We use a variety of devices intended to prevent damage due to sudden spikes from numerous sources. The bottom line is a $70 device isn't going to save your precious electronics. I equate it to a $1500 video display saving a $2 fuse when lighting strikes the service lines. If the select items you own are worth protection then you'll have to invest in serious and expensive equipment. There is no free lunch. I use a highend Monster device and even then I 'unplug' it from the wall when I'm leaving for extended periods. It's kinda like using an aspirin between the knees to prevent pregnancy. What can't get there can't cause harm.

 

[ishiboo]

I'm not going to read through this whole diatribe. I work in a network environment worth millions of dollars. We use a variety of devices intended to prevent damage due to sudden spikes from numerous sources. The bottom line is a $70 device isn't going to save your precious electronics. I equate it to a $1500 video display saving a $2 fuse when lighting strikes the service lines. If the select items you own are worth protection then you'll have to invest in serious and expensive equipment. There is no free lunch. I use a highend Monster device and even then I 'unplug' it from the wall when I'm leaving for extended periods. It's kinda like using an aspirin between the knees to prevent pregnancy. What can't get there can't cause harm.

Then don't, but if you're not going to then perhaps you shouldn't bother ranting.

When comparing bottom lines, it's best to compare the actual bottom line. You're comparing just the absolute protection of the devices. A $70 device will suppress many surge situations, and many have connected equipment warranties which will cover connected equipment. Insurance is another factor as well.

Likewise, protecting "millions of dollars of network equipment" is not the sole purpose of surge protection in a data center or similar environment. It's protecting the SERVICES that the equipment provides and everything that can be lost from the short-term unavailability of them... ie potential sales for an e-commerce site.

Kill a couple servers and you've still saved more by not having surge protection on all X of them anyway. Kill a couple core routers or critical database machines and have to wait for them to be replaced/restored/etc., and the downtime far exceeds the cost of the equipment, surge protection, insurance, and everything else. Hardware is cheap in comparison.

Your television typically does not have the same issue, unless you're quite pathetic.

 

[rlitman]

. . . I work in a network environment worth millions of dollars. We use a variety of devices intended to prevent damage due to sudden spikes from numerous sources. The bottom line is a $70 device isn't going to save your precious electronics...

As do I. I can tell you what we use. The first stage of defense utilizes Square D TVSS on the 480V 3 phase building bus. This is the best TVSS money can buy, and the setup was custom engineered for us by Schneider Electric.
We have one at the utility MSS, and one at each of the A and B panels downstream of the two generators.

They retail about $5k per TVSS unit. Each unit has a "hit" counter display, and indicators that show when modules have failed. Each replacement module runs over $1000, and each TVSS unit has three such modules in it.

Over time, I have had to replace several modules. They're pretty much a "black box". But since it was junk anyway, I sawed open one module, just to see how it was constructed. Wouldn't you know it, they contain the EXACT SAME MOV components as a $5 power strip surge suppressor. What makes them special, is that they have more MOVs, and they are encased in a bakelite fire retardant shell, potted in epoxy, since a failure on a 480V system could otherwise cause a nice fireball.

The $70 whole house TVSS I have on my house is no better or worse for MY house. Keeping in mind that the impedance of the aerial feed to my house greatly limits the energy potential of a surge, compared to the lines feeding my work, the relative effectiveness of the two units is about comparable.

The important distinctions between these units, and a cheap plug in surge suppressor, is that a whole house surge suppressor has the potential for a much better impedance to ground (making the MOV most effective), and it has an indicator that tells you when it has failed (as an MOV is a consumable device and needs replacement after dissipating a specific amount of energy).

Anyway, I'm not saying that reading this whole thread is or is not worthwhile, but your rant certainly was not one of its highlights.

BTW, in a Data Center environment, surge suppression is not really important for protecting services.
In a Tier III environment, the UPS power will be generated in an online mode. Either through online inverter UPS, or rotary UPS, or something like that. As mechanical loads are not on the UPS bus (i.e. chillers, DX coolers, etc), surges will not happen on the UPS output, so there is no real risk to the computational load. Surges do shorten the lifetime of other components though, which costs money to repair, so TVSS is a nice safety net to protect other equipment (such as UPS input PFC capacitor banks, etc.).
In a Tier I environment (such as most cloud hosting), equipment loss is just accepted as part of the cost of getting cheaper services. You pay less money, and you take your chances. In the places that offer low PUE numbers, and do so by utilizing high efficiency standby UPS units, TVSS becomes important, as it does actually filter the power going to the computational load, but generally such places are dedicated to a single customer.

 

[wyliesdiesels]

I've done electrical and telecom in sml and lrg data centers and server rooms and I agree with rlitman!

 

[westom]

I'm still curious if anyone else has heard of setting these up at the farthest slot from the lugs.

Question was answered with why some believe it is important.

For example, a voltage is suddenly applied to one end of the wire. On what part of that wire is the voltage first seen? On its fartherest end. Voltage is last seen at the near end where voltage was first applied.

At which slot on the bus might a transient first be seen? Same. At the far end. And then other parameters make that irrelevant.

As noted, both effective and ineffective (but much more expensive) solutions all use MOVs (or something equivalent). Less expensive and superior solutions put more of your money into MOVs and less into profits. And include the critically important and dedicated wire to earth ground. So that even direct lightning strikes do not damage a sufficiently sized protector. A minimal 'whole house' protector will be speced at about 50,000 amps.

That is simple science. The 'art' (and what should have most of your attention) is earthing and how it is connected. Which slot to use makes near zero difference once we consider other parameters that also say why an earthing connection must be so short.

Those layman guidelines for earthing can make or break protection. Which slot creates a near zero difference. Explained (and then requoted) is why some believe it is important.

 

[Tim Kennedy]

Several years ago, my incoming neutral seperated & fried my garage door opener [fortunately that was all] & I asked the repairman about the whole house surge protector. He said they are available from the power co. but in this scenario it would not have done any good [seperated neutral] also told me I was lucky 'cause most of the time when that happens it takes the microwave & a/c out too. Still think I will get one from the power co.

 

[wyliesdiesels]

Several years ago, my incoming neutral seperated & fried my garage door opener [fortunately that was all] & I asked the repairman about the whole house surge protector. He said they are available from the power co. but in this scenario it would not have done any good [seperated neutral] also told me I was lucky 'cause most of the time when that happens it takes the microwave & a/c out too. Still think I will get one from the power co.

A whole surge protector wouldn't have done anything when that happened because the neutral separation didn't cause a surge, it caused an over/under voltage situation on your main 120v legs. Together, they both still equaled 240v but one was under voltage, (say 80v) and the other was over voltage(160v)! This isn't a surge but because of the over voltage, many devices and electronics get fried!

 

[rlitman]

A whole surge protector wouldn't have done anything when that happened because the neutral separation didn't cause a surge. . .

Exactly. MOV devices generally only react to voltages over 440V on a 120/240V system (I would need to look up the clamping voltages on my systems at work, as I don't what what that is off hand for a 480V system).

Placement of the connection from the TVSS to the panel bus will indeed affect the impedance, but yes, there is far more potential for impedance in an improperly prepared ground. That is certainly by far the biggest factor in how well these devices work.

MOVs are not the only class of device to interrupt transient voltages, but they are the state of the art. Gas discharge tubes for example, do not have the lifetime limitations of an MOV, but take far longer to "clamp", and only do so at higher voltages. For protection of electronics, there is nothing better available than MOV, although as I said, MOV devices are consumable. Eventually they wear out (even though there do not appear to be moving parts, you need to treat them as such).